Kiln and burner therefor



June 5, 1923.

E. M. BASSLER KILN AND BURNER THEREFOR Filed March 22. 1920 PatentedJune 1923.

UNITED STATES- ame "Par-agar orrics. '7

EDWIN M. BASSLER, OF MILWAUKEE; WISCONSIN.

xnm AND BURNER THEREFOR.

Application filed. March 222, 1920. Serial No. 867,624.

/ To all whom it may concern Be it known that I, EDWIN M. BABSLER, a

citizen of the United States, and resident of Milwaukee, in the countyof Milwaukee and State of Wisconsin, have invented a new and usefulImprovement in Kilns and Burners Therefor, of which the following-is aspecification.

This invention relates to kilns and relates particularly to burnerstherefor, in which pulverized coal is used for fuel.

Heretofore, in accordance with the common standard practice, thepulverized coal is discharged into the kiln through a fuel supply pipeby means of an air blast of relatively high pressure and velocity, the.

pulverized coal being discharged into said uel supply pipe from a bin orother source of supply by means of a screw conveyor or other sultablemeans.

The volume and velocity of the air used for injecting the coal is variedto suit local conditions, the amount of air introduced beingapproximately only twenty-five per centof the volume of air necessaryfor complete combustion of the coal used. The additional air necessaryto producecomplete combustion of the coal introduced into the kiln issupplied by induced stack draft and enters the kiln through variousopenings. This method of introducing what may be referred to as thesecondary air supply is at best haphazard, being subgect to all changesof draft produced by atmospheric conditions, direction of the wind,etc., and cannot be controlled with any degree of accuracy. Such controlas is possible is effected by regulation of the air blast in the fuelsupply pipe and the stack draft, by means of valves or dampers.

The use of too much air tends to reduce the temperature in the kiln andrequires the use of an excess of fuel to produce the desired temperaturetherein, while the use of too little air causes the generation of gaseswhich are not consumed until after they reach the stack, where theycombine fect oxidation, the reducing actionthereof afiecting the ironand sulphur content of the clinker, and impairing the'colonand thesoundness of the finished product.

- The object of the present invention is to overcome theforegoing-"objectionable features by eliminating, so far as possible,all openings in the kilnthrough which leakage of air may be induced bythe stack draft and provlding means for supplying air tow the kiln,which may be controlled and adjusted so as to supply a volume of air tothe kiln proportioned to efiectcomplete combus ion of the fuel coalsupplied thereto.

In accordance with what I now consider to be the referable embodiment ofmy invention, t e pulverized coal used for fuel pipe b means of a,current of air of relatively igh pressure. As previously stated, thevolume of high pressure air thus admitted to the kiln is much less thanis reis controlled by a valve or damper whereby the quantity of airadmitted therethrough may be separately adjusted and regulated.Preferably, also, the pipe through which air is su plied to the headerwith which said air supp y plpes communicate, is also provided with agate or valve by means of which the volume of air supplied to saidheader may be regulated to meet varyin conditions of atmosphere,direction and ve ocity of wind, e c.

My invention also comprises the various other features, combinationsoffeatures and details of construction hereinafter described and claimed.a

In the accompanying drawings, in which my invention is fullyillustrated,

Figure 1 is aside view of a kiln equipped with a burner of my invention.

Figure 2 is a sectional end view thereof on the line 2+2 of Fig. 1

Figure 3 is a sectional view of the discharge end of the fuel supplypipe'on the line 33 of Figure 2, on an enlarged scale.

Fi re 4 is a sectional view of the fuel supp y pipe on the line 4- 1 ofFig. 3;. and

Figure 5 is a sectional view of one of -is supplied to the kiln througha fuel supply I the secondary air supply pipes on the line of Fig 1.

In the accompanying drawings, I have shown my invention and improvementsas applied in useto a usual form of cement kiln comprising a shellindicated at 1, which is rotatably mounted at a small angle to thehorizontal, the inclination thereof being downwardly towards itsdischarge end; a closure 2 for the discharge end of the shell 1, saidclosure being stationary and being made of suitable refractory material,as firebrick or the like; a fuel supply pipe 3, through which pulverizedcoal is adapted to be delivered into the kiln by a current of air ofsufficiently high pressure and velocity to form a vehicle for saidpulverized coal; a

blower 4 adapted for supplying air under pressure to said fuel supplypipe; a bin 5 for containing the powdered coal to be used I as fuel; anda screw conveyor 6 connected to the lower end of the hopper shapedbottom of the bin 5, adapted to discharge the pulverized coal from saidbin into the fuel supply pipe 3, said screw conveyor being driven from asuitable source of power, not shown, by a belt applied to a pulley 7secured to the projecting end of the shaft of the conveyor screw, orother means.

All of the foregoing features are old and well known in the art, and,excepting as hereinafter particularly described, may be of any usual orapproved construction and will readily be understood by persons familiarwith the art without .a description thereof in detail.

As stated, the air entering the kiln through the fuel supply pipe 3 isonly about twentyfive per cent of the total volume of air nec-.

essary for effecting complete combustion of the fuel supplied to thekiln, and to provide the additional air necessary to effect completecombustion of the fuel and for regulating the quantity of air asnearlyas practicable, to the exact amount necessary to produce completecombustion, I provide what may be referred to as a secondary air supply,preferably of relatively low pressure and velocity. As shown, the meansfor supplying such secondary air consists of a header 8 supportedadjacent to the closure 2 of the kiln and connectedwith a blower bymeans of a pipe 9.

In what I now consider its preferable form, the header 8 forms a segmentof an annular receptacle, and may be described in a general Way assubstantially horse-shoe shaped. Air under pressure is adapted to bedischarged from the header 8 into the rear or discharge end of the kilnby means of pipes 10, which are secured in the wall of said header andthe outer ends of which extend into holes 11 formed in the closure 2 ofthe kiln. As shown, there'is a considerable number of the pipes 10arranged in a valve or damper 12 which affords convenient means forregulating the effective size or area of the plpe opening and which, inuse, is designed to be secured in fixed ad ustment by means of a setscrew or other means.

The valves or dampers 12 in the pipes 10 are provided primarily for thepurpose of proportioning the volume of secondary air to the volume of.high pressure ajir discharged into the kiln through. the fuelsupply pipe3, and, in operation, their adjustment will be substantially permanentor will be changed onl at considerable intervals. The volume of airadmitted to the kiln through the pipe 9 to meet varying conditions ofatmosphere, wind, etc., is adapted to be controlled by a gate or valveindicated Preferable means for supplying high and low pressure air tothe kiln consists of a compound blower, indicated at 4, the pipe 9 beingconnected to the discharge opening of the first or low pressure unit ofsaid blower and the pipe 3 to the discharge opening of the second orhigh pressure unit therefore. may be purchased commercially or can bereadily supplied by persons skilled in the art, and said fan is not,therefore, herein shown or described in detail.

If for any reason desired, my invention contemplates the use of separateblowers for supplying high and lower pressure air to the kiln.

It is found in practice that the pulverized fuel delivered into the fuelsupply pipe-3 by the screw conveyor 6 has a tendency to settle andcollect at the bottom of said fuel supply pipe adjacent to its dischargeend, thereby choking said pipe and destroying the balance between thehigh pressure and the low pressure air. To overcome this objectionablefeature, I provide for discharging jets of air upwardly through thebottom of the section of said pipe where said coal tends to. deposit,said air jets being preferably directed at an angle upwardly and towardsthe discharge end of said fuel supply pipe. Simple means for thispurpose consists of a jacket 14: on the pipe 3, which is connected withsaid pipe 3 by a pipe 15, which communicates with said pipe 3 betweenthe blower 4 and the point where the conveyor 6 discharges into saidpipe. Also, to provide for directing the jets at an an angle upwardlyand towards the discharge end of the pipe 3, the jacket 14 preferablycomprises a plate 16 fitted to the outside of the pipe 3, said pipe 3being cut away beneath said jacket. Said plate 16 is Fans suitable forthe purpose fied in claim 1, in which the secondary air of suchthickness, say one-quarter of an inch,

that jet orifices 17, inclined at a desired angle to give the air jetsdischarged there from a desired direction, may be formed therein.

The pipe 3 is controlled by. a "valve 18 positioned between the pointsat which the pipe 15 leading to the jacket 14 and the screw conveyor 6communicate therewith, thereby providing not only for regulating thevolume of air passing through said fuel supply pipe, but also providingfor diverting a portion of air from the pipe 3 into the pipe 15 andthence into the jacket 14, where it is again discharged into the fuelsupply pipe in the form of air jets in the manner described. Preferably,also, the pipe 15 is controlled by a valve 19.

Also, if desired, my invention contemplates the use of a lip or wing 20on the inside of the pipe 3 for diverting air from said pipe into thepipe 15.

I claim:

1. The combination of a kiln anda burner therefor, said burnercomprising a fuel supply pipe, means for creating a current of airtherethroughforming a primary air supply, a header, pipes which connectsaid header with the interior of the kiln and are spaced radially fromsaid fuel supply pipe, and means for supplying air under pressure tosaid header forming a secondary air suppl said secondary air supplybeing of relative ylow pressure and large volume as compared with theprimary air supply, substantially as described.

2. A kiln and a burner therefor. as specisupply pipes discharge into thekiln adjacent to theshellthereof, substantially as described. A A

3. A kiln and a burner therefor as specified in claim 1,in-which thefuel supply pipe and the secondary-air supply pipes are arrangedsubstantially centrally and adjacent to the shell of the kiln,respectively, substantially as described.

4. A kiln and a burner therefor as specified in claim 1, in which thesecondary air I supply, pipes are arranged in series, the extreme pipesof :which are spaced a considerable distance above the bottom of theshell of the kiln, substantially as described.

5. A kiln and a burner therefor as specified in claim 1, comprisingmeans for delivering pulverized fuel into the fuel supply pipe, andmeans for preventing the deposit of fuel therein,"comprising a jacketwhich encloses the under side of said fuel supply pipe, a wallseparating said jacket and fuel supply pipe provided with jet openings,a pipe which connects said jacket with the fuel supply pipe between themeans for supplying air under pressure to said fuel supply pipe and thepoint at which fuel is delivered into the same, and means for divertinga sufiicient volume of air from said fuel supply pipe into said jacketto create a differential pressure in said jacket greater than thepressure in the section of the fuel supply pipe which said jacketencloses, substantially as described.

6. A kiln and a burner therefor as specifled in claim 5, in which avalve is connected into the fuel supply pipe between the points wherethe pipe connecting said fuel supply pipe and jacket communicates withsaid fuel supply pipe and fuel is delivered thereto, substantially asdescribed.

7.- A kilnand a burner therefor as specified in claim 6,. in whichthere'is a lip in the fuel supply pipe adapted to' divert air; therefrominto the pipe whichconnects said fuel supply pipe jacket, substantiallyas described.

In testimony that I claim the foregoing as my invention, I affix mysignature this 12th dayof March, 1920.

EDWIN M. BASSLER.

